Brianna Horrigan was surprised to see all the silky, sparkly dresses on racks in a rainbow of colors as she ventured into the Hamburg dance studio, where eager girls had waited in line outside for the start of the prom gown giveaway.

“I didn’t think there would be as many gorgeous dresses as there were,” said Horrigan, 16, a junior at Eden High School, holding up a the dress with sequins and frills in a bright shade of baby blue she had ultimately chosen.

“It definitely helped with money,” she said Saturday afternoon. “Not a lot of people have money and I’m definitely one of those people.”

Finding a dress at the fourth annual Shopping Days, which she saw advertised on a poster at school, was an alternative to buying a dress with “money that I didn’t have.” The event, which also will be held from noon to 3 p.m. today in the Performing Arts Dance Academy, 206 Lake St., is the first of two giveaways in the region.

Collected with the help of dry cleaners and volunteers, the free dresses are intended to ease the burden of an increasingly expensive rite of passage. Dresses for a formal dance can cost from $100 to $200, and many tux rentals cost close to that. Tickets to the Eden prom are $70 each, a typical price.

“It’s ridiculous,” said Horrigan, who works at a farm taking care of horses to earn the money to cover her prom expenses.

Shopping Days was the culmination of months of organizing by County Legislator Lynne Dixon, I-Hamburg, and her staff and other volunteers. Last month, they collected about 600 lightly worn dresses from Urban Valet dry cleaner locations, as well as from a school and even from an exercise class for moms.

This year’s event, said Dixon, was the best so far, with more dresses donated by more people. From the start on Saturday, the girls rushing to cars with gowns wrapped in protective dry cleaner bags were grateful.

“The first couple of girls that came through, they found the dresses that they wanted and they were very excited,” Dixon said. “It makes me feel happy.”

Dixon launched the project after the Eden Boys and Girls Club asked for a giveaway similar to one held in Buffalo.

The ninth annual Gowns 4 Proms will be held at Shea’s Performing Arts Center from 3 to 7 p.m. Monday, Tuesday and Wednesday. All interested girls are welcome and should register through their school or online at colvincleaners.com, said Tony Billoni, owner of Colvin Cleaners, an organizer of the event.

Billoni said he likes helping families save on what can be a substantial expense. “The children are so courteous and polite and thankful,” he said.

Kayla McKinnis, 18, arrived at Saturday’s event with her mother to shop for a dress for her McKinley High School prom. With class dues and tickets to the dance costing $150, she will get help from her grandmother to pay for it all.

After trying on a lemon yellow dress with rhinestones, she went for a black dress with a front that laced up over a panel of white. Between now and the May prom, she still has to figure out her shoes, jewelry and hair. The young woman said she wasn’t worried about a date.

“So many choices,” said her mother Charlesetta McKinnis, smiling.

What matters most, said her daughter, is being with her friends for a party before they separate and go off to college.

“It’s very important,” she said, “because it’s our last time to celebrate.”